The present invention relates to a distorted waveform signal generator for generating signals with distorted waveforms, such as musical tone signals.
A conventional rhythm sound source for generating a rhythm sound with a timbre of the cymbals, for example, has generally been composed of a generator for generating distorted waveform signals having a timbre like the cymbals. In the generator, a trigger pulse is applied to a resonance circuit to generate a damping sinusoidal wave signal. A trigger pulse and white noise are applied to an envelope generator to obtain a white noise having a prescribed envelope waveform. The envelope waveform signal is applied to a low-pass filter to remove high frequency components from the envelope waveform signal. The output signal from the low-pass filter and the damping sinusoidal waveform signal are mixed. In this way, the distorted waveform signal is formed in an analog circuit.
In the case of the analog circuit, various characteristics of the circuit are greatly influenced by factors such as parts error and ambient temperature drift. The property of the sound, particularly timbre, is very sensitive to such factors. To cope with the problem, a circuit for removing such influence is additionally required. The use of the additional circuit makes it difficult to fabricate the generator by the LSI technology. Additional disadvantages of the conventional generator are the increased number of parts, an increased chip area as occupied, and complicated circuitry, and high cost to manufacture.